Narrative:The flight was assigned an airspeed of 230 knots and cleared to descend from FL240 to 16,000 feet in preparation for landing at Miami. The FDR indicated that while the autopilot was engaged in the descent, the power levers moved from the mechanical autothrottle limit of 44 degrees to the manual limit of 37 degrees. As the aircraft leveled at 16,000 feet the airspeed decreased. The F/O began a right turn to enter a holding pattern and added some power, which stabilized the airspeed at 178 knots. However, the right bank and the resultant angle of attack (AOA) continued to increase, despite left aileron input by the autopilot. As the autopilot reached the maximum input of 20 degrees, bank angle increased past 50 degrees, and the AOA increased rapidly from 7 degrees to 12 degrees. At this point the stick shaker activated, the autopilot independently disconnected, the power was increased, and full left rudder was used to arrest the roll. The bank angle reached 56 degrees, and the AOA reached 13.7 degrees at 177 knots. The aircraft then pitched down, and entered a series of pitch, yaw, and roll maneuvers as the flight controls went through a period of oscillations for about 34 seconds. The maneuvers finally dampened and the crew recovered at approximately 13,000 feet. One passenger was seriously injured and one flight attendant received minor injuries during the upset. An analysis showed that the forces during the upset not only had gone above the design limit of the vertical stabilizer, they also apparently had reached the ultimate limit. In June 1997, Airbus requested that American Airlines perform another inspection of the jet to ensure it was not damaged. American inspectors, following Airbus' instructions, examined the tail fin. But they did not use methods that would have allowed them to see inside the tail fin. They saw no damage from their visual inspection, and the jet continued to fly until an ultrasound inspection of the horizontal stabilizer was done in March 2002. The inspection found two crescent-shaped cracks at one of the points where the tail fin attaches to the fuselage. The fin was replaced.

PROBABLE CAUSE:"The flightcrew's failure to maintain adequate airspeed during leveloff which led to an inadvertent stall, and their subsequent failure to use proper stall recovery techniques. A factor contributing to the accident was the flightcrew's failure to properly use the autothrottle."

Sources:

» NTSB» USA Today 27-5-2003

Follow-up / safety actions

NTSB issued 5 Safety Recommendations

Issued: 21-JAN-1998

To: FAA

A-98-003

REQUIRE THAT AIRBUS INDUSTRIE MODIFY THE SYMBOL GENERATOR UNIT (SGU) COMPUTER SOFTWARE INSTALLED IN THE A300 SO THAT AN UNRELIABLE DATA RESET OF THE ELECTRONIC FLIGHT INFO SYSTEM WILL NOT OCCUR DURING AN UPSET. WHEN THE MODIFIED SOFTWARE IS AVAILABLE, REQUIRE THAT ALL OPERATORS INSTALL IT IN THE SGUS. (Closed - Acceptable Action)

Issued: 21-JAN-1998

To: FAA

A-98-004

ISSUE A FLIGHT STANDARDS INFO BULLETIN TO DIRECT PRINCIPAL OPERATIONS INSPECTORS TO ENSURE THAT AIRBUS INDUSTRIE A300 OPERATORS NOTIFY FLIGHTCREWS OF THE POSSIBILITY OF A TEMPORARY LOSS OF ELELCTRONIC FLIGHT INSTRUMENT SYSTEM DISPLAYS DURING AN UPSET. (Closed - Acceptable Action)

Issued: 21-JAN-1998

To: FAA

A-98-005

COMPARE THE DESIGN OF THE A300 AUTOTHROTTLE SYSTEM WITH SIMILAR TRANSPORT-CATEGORY AIRPLANES, & DETERMINE IF ADDITIONAL VISUAL/AURAL WARNINGS ARE NECESSARY TO ENSURE THAT FLIGHTCREWS ARE AWARE THAT THEY HAVE MANUAL CONTROL OF THE THROTTLE. IF ADDITIONAL WARNINGS ARE NECESSARY, AIRBUS INDUSTRIE SHOULD BE REQUIRED TO MODIFY THE A300 ACCORDINGLY. (Closed - Acceptable Action)

Issued: 28-MAY-2004

To: FAA

A-04-044

Require Airbus to develop a design modification for the A300-600 rudder travel limiter system so that it can respond effectively to rapid airspeed changes such as those that might be experienced during upsets and not be adversely affected by pedal forces, and issue an airworthiness directive to require the installation of that modification. (Open - Acceptable Response)

Issued: 28-MAY-2004

To: FAA

A-04-045

Evaluate other transport-category airplanes with rudder limiting systems to determine whether any of those systems are unable to effectively respond to rapid airspeed changes such as those that might be experienced during upsets, or whether any of those systems are adversely affected by pedal forces and, if so, require corrective modifications to those systems. (Closed - Acceptable Action)

This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path. Distance from Boston-Logan International Airport, MA to Miami International Airport, FL as the crow flies is 2014 km (1259 miles).